1. Field of the Invention
The invention relates to the prevention or reduction of amine and N-nitrosamine formation during the production and use of elastomers.
2. Description of Related Art
Volatile N-nitrosamines can be released to the environment from elastomeric articles. These N-nitrosamines in turn can be formed from caoutchouc chemicals (for example activators, accelerators, sulphur donors and retarders) which contain amines in the combined state. N-nitrosamines likewise already form during the processing of caoutchouc compounds. In the formation of these compounds, both NO.sub.x (for example adsorbed on elastomeric constituents or from the surrounding air) and the corresponding secondary amines are involved.
The nitrosamine problem has been known in the rubber industry for many years. The pressure to eliminate carcinogenic N-nitrosamines is being intensified by laws prescribing maximum concentrations. In Caoutchour+Rubber Plastics, Vol. 43 (1990), No. 2, pp. 107-113, the use of inhibitors is examined to bond the critical secondary amines. In particular, tests with oxime-blocked isocyanates to inhibit methyl phenylamine from dimethyl diphenyl thiuram disulphide resulted in no reduction in the NMPhA quantity being liberated. Therefore this method is regarded by the authors as ineffective in the case of a dose of blocked isocyanate customary for elastomers.